Auxiliary power supply system for high power loads in a hybrid/electric vehicle

ABSTRACT

An apparatus includes a first interface a second interface, a third interface and a converter. The first interface may be configured to exchange a high-voltage signal with a high-voltage battery of a vehicle. The second interface may be configured to receive a first low-voltage signal from a source external to the vehicle. The third interface may be configured to present a second low-voltage signal to a power rail of the vehicle. The converter may be configured to (i) generate the high-voltage signal by up-converting the first low-voltage signal while in an up-conversion mode to recharge the high-voltage battery of the vehicle and (ii) generate the second low-voltage signal on the power rail by down-converting the high-voltage signal received from the high-voltage battery while in a down-conversion mode.

This application relates to Italian Application No. 102018000006790,filed Jun. 28, 2018, which is hereby incorporated by reference in itsentirety.

FIELD OF THE INVENTION

The invention relates to vehicle power systems generally and, moreparticularly, to a method and/or apparatus for implementing an auxiliarypower supply system for high power loads in a hybrid/electric vehicle.

BACKGROUND

Improvements in electronics for modern hybrid/electric automobilesresult in high current demands. While the automobile is running, alimited amount of current is available. The amount of current isdetermined by the manufacturer to meet a maximum current that theautomobile systems can consume. A small “extra” current capacity iscommonly left in reserve. After-market high-power loads added to theautomobile typically exceed the reserve current capacity of the powersource. Furthermore, when the automobile is not running, conventionalbatteries typically cannot meet the steady-state current demands of thehigh-power loads. If the batteries can satisfy the loads, the batteriesare usually drained in a short time. A conventional solution is toprovide additional batteries to lengthen the battery-only time. However,the additional batteries consume a large amount of space and addsignificant weight to the automobile.

It would be desirable to implement an auxiliary power supply system forhigh power loads in a hybrid/electric vehicle.

SUMMARY

The invention concerns an apparatus including a first interface a secondinterface, a third interface and a converter. The first interface may beconfigured to exchange a high-voltage signal with a high-voltage batteryof a vehicle. The second interface may be configured to receive a firstlow-voltage signal from a source external to the vehicle. The thirdinterface may be configured to present a second low-voltage signal to apower rail of the vehicle. The converter may be configured to (i)generate the high-voltage signal by up-converting the first low-voltagesignal while in an up-conversion mode to recharge the high-voltagebattery of the vehicle and (ii) generate the second low-voltage signalon the power rail by down-converting the high-voltage signal receivedfrom the high-voltage battery while in a down-conversion mode.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the invention will be apparent from the followingdetailed description and the appended claims and drawings in which:

FIG. 1 is a diagram of a vehicle in accordance with an embodiment of theinvention;

FIG. 2 is a diagram of an electrical system of the vehicle accordancewith an embodiment of the invention; and

FIG. 3 is a state transition diagram of an electronic control unit ofthe electrical system in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention include providing an auxiliarypower supply system for high power loads in a hybrid/electric vehiclethat may (i) provide an after-market technique to accommodate high-powerelectrical loads, (ii) provide current beyond a main power distributionsystem capacity, (iii) power electrical loads for a long time while anengine is switched off, (iv) operate from electrical power received froma wall source (v) operate from electronic power received from anauxiliary source and/or (vi) provide uninterrupted electrical powerwhile hot-swapping between power sources.

Embodiments of the invention generally provided an auxiliary powersystem and auxiliary power distribution technique that are capable ofpowering a secondary power bus independent from a main electrical bus ofa hybrid or electric type vehicle (e.g., automobile, truck, bus, etc.).A vehicle power source of the hybrid type vehicle may generateelectrical power derived from an internal combustion engine. A mainhigh-voltage battery of an all-electric type vehicle may provide theelectrical power. Use of electrical power from the internal combustionengine and vehicle power source and/or the main high-voltage battery maybe considered a “vehicle powered mode.”

In hybrid type vehicles, a generator (or alternator) in the vehiclepower source may provide high-voltage power to charge the mainhigh-voltage battery. In all-electric type vehicles, an AC/DC convertermay convert external AC power to generate the high-voltage power tocharge the main high-voltage battery. The vehicle power source and/orthe main high-voltage battery may provide electrical power to a vehicleDC/DC down-converter that generates low-voltage electrical power on amain power bus. The high-voltage electrical power may also be shared bythe auxiliary power system and, if present, an electric drive system.The secondary power bus and the main power bus may be electricallyindependent and physically separate from each other. The secondary powerbus may be operational while the engine (e.g., an internal combustionengine or electric drive engine) of the vehicle is switched off.

Various embodiments of the invention may utilize the auxiliary powersystem to provide electrical power to high power loads connected to thesecondary power bus. In some cases, the high power loads may be loadsthat draw on average more electrical current than the vehicle powersource may produce and/or the main power bus may distribute. In varioussituations, the high power loads may be loads the draw surge currentsgreater than a capacity of the vehicle power source and/or the mainpower bus without impacting the rest of the vehicle electronics. In someembodiments, the auxiliary power system may provide up to 15 kilowatts(kW) of power to the secondary power bus for extended periods. Forexample, the auxiliary power system may provide 1.5 kW of power to loadson the secondary power bus from a 10 kW hour (kWh) capacity battery forup to 6.4 hours, 5 kW of power from a 30 kWh capacity for 6 hours, and15 kW of power from a 100 kWh capacity for up to 6.4 hours after thehybrid vehicle engine is switched off and the main high-voltage batteryis fully charged.

In various embodiments, the auxiliary power system may receiveelectrical power from an AC powered battery charger connection and/oranother source (e.g., an auxiliary power unit) inside and/or outside thevehicle. Distribution of electrical power from the battery charger maybe referred to as a “wall powered mode.” Distribution of electricalpower from the auxiliary power unit may be referred to as an “auxiliarypower mode.” The battery charger may drive the high power loads for anunlimited amount of time during indoor employment or outdoor employment(e.g., software testing, etc.) with the hybrid vehicle engine off or theelectric vehicle main high-voltage battery nearly discharged. Theunlimited engine-off/low main high-voltage battery charge operation ofthe high power loads may allow sufficient time to perform diagnostics,uploading and/or downloading of information to and from the electronics.For example, data gathered and stored during autonomous-driving tripsmay be downloaded from autonomous driving computers powered through thesecondary power bus while the vehicle is inside a garage. Electricalpower from the battery charger and/or auxiliary power unit may also beused to charge one or more batteries internal to the auxiliary powersystem.

The auxiliary power system may provide limited electrical power to thesecondary power bus in the absence of power from the main high-voltagebattery, the battery charger and the auxiliary power unit. The auxiliarypower system may also enable hot swapping among the various sources ofelectrical power. A backup battery internal to the auxiliary powersystem generally allows smooth switching among the vehicle power mode,the wall power mode and the auxiliary power mode without interrupting orcompromising operations of the loads that rely on power from thesecondary power bus.

Referring to FIG. 1, a diagram of an example implementation of a vehicle70 is shown in accordance with an embodiment of the invention. Thevehicle 70 may be an automobile, a truck, a bus, or any other passengerand/or cargo carrying vehicle powered by an engine. The vehicle 70 mayinclude an engine compartment (or area), a passenger compartment (orarea) and a trunk compartment (or area). The vehicle 70 generallycomprises the engine 72, a device (or circuit) 81, a device (or circuit)83, a device (or circuit) 84, a device (or circuit) 86, a device (orcircuit) 88, a device (or circuit) 90, a device (or circuit) 92, adevice (or circuit) 94 and a device (or circuit) 100.

A signal (e.g., CSA) may be transferred between the device 92 and thedevice 100. The command/status signal CSA may carry command data andstatus data between the devices 92 and 100. A signal (e.g., LVA) may begenerated by the device 81 and transferred by the device 88 to thedevices 84, 86 and 100. The signal LVA may implement a low-voltage powersignal. In various embodiments, the low voltage in the signal LVA mayrange from approximately 10 volts DC to approximately 50 volts DC. Asignal (e.g., LVB) may be generated by the device 100 and transferred tothe device 94 via the device 90. The signal LVB may implement anotherlow-voltage power signal. The voltage in the signal LVB may be similarto the voltage in the signal LVA. A signal (e.g., HVA) may be exchangedbetween the device 83 and the device 100. The signal HVA may represent ahigh-voltage power signal. In various embodiments, the voltage of thesignal HVA may range from approximately 200 volts direct current (VDC)to approximately 600 VDC.

The engine 72 may implement an internal combustion engine in a hybridtype of vehicle 70. The engine 72 may implement an electric drive enginein an all-electric type of vehicle 70. The engine 72 is generallyoperational to provide mechanical power to a transmission of the vehicle70 and, wherein implemented, a generator in the device 81. In variousembodiments, the high-voltage generated by the generator may range fromapproximately 200 VDC to approximately 600 VDC.

The device 81 may implement a vehicle power source of the hybrid-typevehicles and/or the electric-type vehicles. The vehicle power source 81may be operational to provide low-voltage electrical power in the signalLVA for the devices 84 and 86. The vehicle power source 81 may also beoperational to provide high-voltage power for the devices 83 and 100.

The device 83 may implement a main high-voltage battery of thehybrid-type vehicles and/or the electric-type vehicles. The mainhigh-voltage battery 83 may be operational to provide high-voltageelectrical power to the device 100 and one or more drive motors of thevehicle 72. In various embodiments, the storage voltage of the mainhigh-voltage battery 83 may range from approximately 200 VDC toapproximately 600 VDC. Bigger vehicles may accommodate higher capacitybatteries and/or more than one battery 83. The main high-voltage battery83 may be charged and/or discharged by the device 100 through the signalHVA and through the vehicle power source 81.

The device 84 may implement a battery. In various embodiments, thebattery 84 may be a normal automotive (or vehicle) battery. The vehiclebattery 84 may be charged by the vehicle power source 81 via the signalLVA. The vehicle battery 84 may provide electrical power in the signalLVA to other electronics in the vehicle 70 while being discharged. Thelow-voltage generated by the vehicle battery 84 may range fromapproximately 8 volts DC to approximately 50 volts DC. The vehiclebattery 84 is generally located in the engine compartment.

The device 86 may implement vehicle service load devices (or circuits).The service load devices (or service loads for short) 86 may receiveelectrical power from the vehicle battery 84 and/or the vehicle powersource 81 in the signal LVA. The vehicle service loads 86 may include,but are not limited to, exterior lighting, interior lighting, electroniccontrol units, door locks, window motors, wiper blades, fans, radio, airconditioning, seat heaters, seat adjustments and the like. The vehicleservice loads may be located throughout the vehicle 70, in the enginecompartment, the passenger compartment, the trunk and/or otherlocations.

The device 88 may implement a main low-voltage bus (or power rail, orharnessing, or wiring). The main low-voltage bus 88 may be operationalto distribute the signal LVA among the vehicle power source 81, thevehicle battery 84 and the vehicle service loads 86. In variousembodiments, the main low-voltage bus 88 may utilize the vehicle chassisas a ground bus.

The device 90 may implement an auxiliary low-voltage bus (or power rail,or harnessing, or wiring). The auxiliary low-voltage (or secondary) bus90 may be operational to distribute the signal LVB from the device 100to the device 94. The auxiliary low-voltage bus 90 may be electricallyisolated from the main low-voltage bus 88. The isolation may includeseparate hot wires and separate ground wires from the main low-voltagebus 88. In various embodiments, the low voltage generated by the device100 in the signal LVB may range from approximately 10 volts DC toapproximately 50 volts DC.

The device 92 may implement a user interface device (or circuit). Theuser interface device 92 may be operational for bidirectionalcommunication with the device 100 via the signal CSA. The communicationsmay be based on an Ethernet protocol, a Controller Area Networkprotocol, a Universal Serial Bus protocol or similar standardtechniques. Information conveyed by the signal CSA may include, but isnot limited to systems status, current energy source status, flowingcurrent, voltages and estimated remaining time using the mainhigh-voltage battery 83 at the current rate (while the internalcombustion engine 72 is off in a hybrid-type vehicle 70). The userinterface device 92 may allow a user to switch between different energysources and/or different system status indicators. The user interfacedevice 92 is generally located in the passenger compartment.

The device 94 may implement one or more high-power on-vehicle loaddevices (or circuits). The high-power load device (or high-power loadsfor short) 94 may receive electrical power from the device 100 in thesignal LVB. The high-power loads 94 may include, but are not limited to,cooling system, autonomous driving computers, advanced drivingassistance systems, multimedia systems, computers, actuators andcleaning systems for sensors. The high-power loads 94 may be located inmultiple locations about the vehicle 70 including, but not limited to, aroof space, a trunk, external parts of the shell (or body), a passengercabin and the like.

The device 100 may implement an auxiliary power system. The auxiliarypower system (or circuit or unit) 100 may be operational to providelow-voltage electrical power in the signal LVB to the high-power loads94. The auxiliary power system 100 may also be operational to providehigh-voltage electrical power in the signal HVA to charge the mainhigh-voltage battery 83. The auxiliary power system 100 may beoperational to store electrical energy in one or more internal batteriesto provide a limited storage capacity in a small physical area and/or toprovide for uninterrupted power to the high-power loads during modeswitches. The auxiliary power system 100 is generally located in thetrunk and may be accessible to a user while the trunk door is open. Someparts, such as DC/DC converters, may utilize liquid cooling and so maybe installed in the engine bay and linked to the engine or other coolingsystem.

Referring to FIG. 2, a diagram of an example implementation of anelectrical system 80 of the vehicle 70 is shown in accordance with anembodiment of the invention. The electrical system 80 generallycomprises the vehicle power source 81, the main high-voltage battery 83,the vehicle battery 84, the vehicle service loads 86, the mainlow-voltage bus 88, the auxiliary low-voltage bus 90, the user interfacedevice 92, the high-power loads 94 and the auxiliary power system 100.

The vehicle power source 81 generally comprises a device (or circuit)96, a device (or circuit) 97 and a device (or circuit) 98. The auxiliarypower system 100 generally comprises a device (or circuit) 106, a device(or circuit) 110, a device (or circuit) 112 and a device (or circuit)114. The main high-voltage battery may be connected to the auxiliarypower system 100 at an interface (or port) 121. The auxiliarylow-voltage bus 90 may connect to the auxiliary power system 100 at aninterface (or port) 122. An interface (or port) 124 may connect theauxiliary power system 100 to another low-voltage power source. Theauxiliary power system 100 may include an interface (or port) 126connected to the user interface device 92.

The signal LVA may be exchanged at an interface between the mainlow-voltage bus 88 and the device 97. The signal LVB may be presentedfrom the device 108 to the device 112 and the interface 122 of theauxiliary power system 100. A signal (e.g., LVC) may be exchangedbetween the device 106 and the device 108. The signal LVC may be alow-voltage signal. A voltage carried by the signal and LVC may besimilar to the voltage in the signal LVB. A signal (e.g., LVD) may betransferred from the device 110 to the device 108. The signal LVD may bea low-voltage signal. A voltage carried by the signal and LVD may besimilar to the voltage in the signal LVB. A signal (e.g., LVE) may bereceived by the device 108 from a source external to the auxiliary powersystem 100. The signal LVE may be a low-voltage signal. A voltagecarried by the signal LVE may be similar to the voltage in the signalLVB.

The signal HVA may be exchanged between the interface 121 of theauxiliary power unit 100 and a secondary interface of the mainhigh-voltage battery 83. A signal (e.g., HVB) may be generated by thedevices 96 and/or 98 and transferred to the main high-voltage battery 83and the device 97. The signal HVB may implement a high-voltage signal.The high-voltage signal HVB may range from approximately 200 VDC toapproximately 600 VDC. The signal HVB may be received at a primaryinterface of the main high-voltage battery 83. In various embodiments,the primary interface and the secondary interface of the mainhigh-voltage battery 83 may be the same interface. In other embodiments,the primary interface and the secondary interface of the mainhigh-voltage battery 83 may be separate interfaces.

The signal CSA may be exchanged between the user interface device 92 andthe device 114 through the interface 126. A signal (e.g., CSB) may beexchanged between the device 108 and the device 114. The command/statussignal CSB may convey commands and data between the devices 108 and 114.A signal (e.g., CMD) may be exchanged between the device 106 and thedevice 114. The command/data signal CMD may carry commands and databetween the devices 106 and 114.

The device 96 may implement a vehicle high-voltage generator. Thevehicle high-voltage generator 96 is generally operational to generatehigh-voltage electrical power in the signal HVB based on the mechanicalpower received from the internal combustion engine 72. The vehiclehigh-voltage generator 96 may be absent from the electric-type vehicles.

The device 97 may implement a vehicle DC/DC converter. The vehicleconverter 97 may be operational to down-convert the high-voltage signalHVB to generate the low-voltage signal LVA. The vehicle converter 97 maybe implemented in both the hybrid-type vehicles and the electric-typevehicles.

The device 98 may implement an AC/DC electrical device. The AC/DCelectrical device 98 is generally operational to generate the signal HVBfrom an external power source (e.g., AC wall power). The AC/DCelectrical device 98 may be implemented in the electric-type vehicles torecharge the main high-voltage battery 83. The AC/DC electrical device98 may be optional in the hybrid-type vehicles.

The device 106 may implement a DC/DC converter. In various embodiments,the converter 106 may implement a down-converter circuit. As adown-converter, the converter 106 may generate the low-voltage signalLVC by down-converting the high-voltage signal HVA received through theport 121. In some embodiments, converter 106 may implement abidirectional converter. Control between down-converting andup-converting may be based on commands received in the signal CMD. As adown-converter, the bidirectional converter 106 may generate thelow-voltage signal LVC by down-converting the high-voltage signal HVA.As an up-converter, the bidirectional converter 106 may generate thehigh-voltage signal HVA by up-converting the low-voltage signal LVC. Invarious embodiments, the converter 106 may down-convert up to 15,000watts of power. The converter 106 may also up convert up to 15,000 wattsof power.

The device 108 may implement a power switch (or switch for short). Theswitch 108 may be operational to control connecting and disconnectingthe various low-voltage signals LVB, LVC, LVD and/or LVE using manualcontrol and/or electrical control. Where manual control is implemented,the switch 108 may include a manual knob (or lever) accessible from anexterior of a housing of the auxiliary power system 100. The auxiliarypower system 100 may be positioned in the trunk of the vehicle 70 suchthat the manual knob of the switch 108 is readily accessible to a user.Where electrical control is implemented, the switch 108 may communicatewith the device 114 via the signal CSB.

In various embodiments, the switch 108 may be a double-pole N-throwswitch. The value of N may range from 2 to 4, depending on the number ofpower sources available to the auxiliary power system 100. The switch108 may be operational to route low-voltage power among the signals LVB,LVC, LVD and the LVE. In various embodiments, the switch 108 may beimplemented as a break-before-make type of switch. In other embodiments,the switch 108 may be implemented as a make-before-break type of switch.In an example configuration, the switch 108 may connect and disconnectthe signals LVC and LVB (e.g., 2P1T). In another example configuration,the switch 108 may switch the signal LVB between the signals LVC and LVD(e.g., 2P2T). In still another configuration, the switch 108 may switchthe signal LVB between the signals LVC, LVD and LVE (e.g., 2P3T). Theswitch 108 may also be configured to connect the signal LVD or thesignal LVE to the signal LVC to charge the main high-voltage battery 83through the device 110. The switch 108 may also be configured to connectthe signal LVD to the signals LVB and LVC simultaneously to charge boththe main high-voltage battery 83 and the device 112 through the device110.

The device 110 may implement a battery charger plug (or wall plug). Thebattery charger plug 110 may be operational to generate the signal LVDfrom a power source external to the vehicle 70. In various embodiments,the power source may be a 120-volt alternating current (VAC) to directcurrent (VDC) power converter. Other power sources may be implemented tomeet the design criteria of a particular application.

The device 112 may implement another low-voltage battery. Thelow-voltage battery 112 may be referred to as an auxiliary system backupbattery. The auxiliary system backup battery 112 may be operational tostore up to 100 ampere hours with a high in-rush current. The auxiliarysystem backup battery 112 generally allows a smooth switching betweenthe vehicle mode and the wall power mode with the system on, withoutinterrupting or compromising an ability to deliver power to thehigh-power loads 94. In various embodiments, the auxiliary system backupbattery 112 may be located inside a housing of the auxiliary powersystem 100.

The device 114 may implement an electronic control unit (ECU). Theelectronic control unit 114 is generally operational to control theswitch 108 and the converter 106 in response to commands received fromthe user interface device 92. In some designs, the electronic controlunit 114 may be aware of a running/not running status of the engine 72.

During operations, the vehicle converter 97 generally steps down thehigh-voltage power in the signal HVB to create the signal LVA.Down-converting to the lower voltage may reduce a current value flowingin the signal HVB relative to the signal LVA. The main high-voltagebattery 83 may provide high-voltage electrical power to the auxiliarypower system 100 in the signal HVA. The converter 106 within theauxiliary power system 100 may generate the low-voltage power in thesignal LVC. The low-voltage power in the signal LVC may be used internalto the auxiliary power system 100 and distributed to the high-powerloads 94 in the signal LVB. Each signal LVC, LCD and/or LVE may also berouted to the auxiliary system backup battery 112 through the switch 108as the signal LVB.

Since the high-power loads 94 generally draw power through the auxiliarypower system 100, the total amount of power drawn may exceed thecapacity of the vehicle power source 81 for a limited amount of time.With the main high-voltage battery 83 operating at or near fullcapacity, the auxiliary power system 100 may maintain generation of thelow-voltage signal LVB by drawing additional electrical power from themain high-voltage battery 83. In some situations, the high-power loads94 may draw more total power than the capacity of the converter 106.Therefore, the excessive power demands by the high-power loads 94 may besupplemented from the auxiliary system backup battery 112.

The signal LVD provided by the battery charger plug 110 may be routed tothe high-power loads 94 and the auxiliary system backup battery 112through the switch 108. The signal LVD may be derived from an externalDC power supply used for indoor testing, software updating, datadownloads and/or battery charging. The signal LVE may also be providedto the switch 108 through the auxiliary connector 124. The auxiliaryconnector 124 may receive low-voltage power from an auxiliary powersource, such as a solar panel on a roof of the vehicle 70, or any otherlow-voltage power source available.

The converter 106 may be commanded to work in reverse mode andup-convert the low-voltage power in the signals LVD or LVE into thehigh-voltage power in the signal HVA. Operating the converter 106 as anup-converter may allow a recharge of the main high-voltage battery 83using power taken from the battery charger plug 110 or from theauxiliary connector 124. A user may send commands and/or check DC/DCconverter status using control and status signals in the signal CMD. Theuser can also manually and/or remotely control the switch 108 and checkstatus of the switch 108 via the signal CSB.

Installation of the auxiliary power system 100 in the vehicle 70 mayresolve issues with limited power available from the power source 81.The power source 81 is generally designed for a maximum power demand anda small percentage of extra available power sized for safety. Thehigh-voltage power pulled from main high-voltage battery 83 may becurrent limited to avoid damaging main high-voltage battery 83. Invarious embodiments, the electronic control unit 114 may know theinstantaneous amount of current used by the high-power loads 94. Theelectronic control unit 114 may dynamically control the converter 106 toadjust the amount of output current drawn from the main high-voltagebattery 83.

The auxiliary power system 100 generally takes the stored high-voltagepower from the main high-voltage battery 83 as the high-power loads 94demand. The high-voltage power may be converted to the low-voltage usingthe converter 106. The low-voltage power in the signal LVB on theauxiliary low-voltage bus 90 may be physically and electrically separatefrom the signal LVA on the main low-voltage bus 88. Keeping the twopower systems separate from each other generally avoids malfunctions ofthe original equipment manufacturer systems caused by issues on theauxiliary loads. For example, a failure of one or more high-power loads94 may corrupt the auxiliary low-voltage bus 90 but the vehicle 70 maystill be started and moved using the main low-voltage bus 88.

Referring to FIG. 3, a state transition diagram 140 of an exampleimplementation of the electronic control unit 114 is shown in accordancewith an embodiment of the invention. The state transition diagram 140generally provides multiple (e.g., five) states, including a state (ormode) 142, a state (or mode) 144, a state (or mode) 146, a state (ormode) 148 and a state (or mode) 150. The states 142 to 150 may beconsidered the states of the electronic control unit 114, the states ofthe auxiliary power system 100, the states of the electrical system 80and/or the states of the vehicle 70.

The state 142 may implement an internal combustion engine on poweredmode. While in the state 142, if the engine 72 of the hybrid vehicle 70is generating mechanical power, the mechanical power may be converted bythe vehicle power source 81 into the high-voltage signal HVB. The signalHVB may be received by the main high-voltage battery 83. The auxiliarypower system 100 may down-convert the signal HVA from the mainhigh-voltage battery 83 to produce the signal LVB that drives thehigh-power loads 94. The signal LVB may also charge the auxiliary systembackup battery 112.

The state 144 may implement a wall powered mode. When the engine 72 ofthe vehicle 70 is stopped (e.g., ICE OFF), the electronic control unit114 may transition to the state 144. While in the state 144, electroniccontrol unit 114 may command the switch 108 to connect the signal LVD tothe signal LVB. If low-voltage power is available from the batterycharger plug 110, the low-voltage power in the signal LVD may be routedthrough the switch 108 to the signal LVB and out to the high-power loads94.

If insufficient electrical power is received from the battery chargerplug 110, the electronic control unit 114 may command the converter 106into the down-conversion mode. The main high-voltage battery 83 mayprovide current to the converter 106 via the signal HVA. The converter106 may generate the signal LVC that is subsequently routed through theswitch 108 to the auxiliary low-voltage bus 90 as the signal LVB.

If the engine 72 is started while the electronic control unit 114 is inthe state 144, the electronic control unit 114 may command the switch108 to change the connection for the signal LVB from the signal LVD backto the signal LVC, if not already connected. The electronic control unit114 may subsequently transition (e.g., ICE ON) back to the state 142.

The state 146 may implement an auxiliary mode state. If the batterycharger plug 110 is unplugged and the engine 72 is off while in thestate 144, the electronic control unit 114 may transition (e.g.,UNPLUGGED) to the state 146. While in the auxiliary mode state 146, theelectronic control unit 114 may command the switch 108 to routelow-voltage power from the signal LVE to the signal LVB. The auxiliarylow-voltage bus 90 may route the power to the high-power loads 94 as thesignal LVB.

If insufficient power is available from the auxiliary connector 124, andsince the engine 72 is not running while in the state 146, theelectronic control unit 114 may command the converter 106 into thedown-conversion mode, and command the switch 108 to connect the signalLVC to the signal LVB. The high-voltage energy stored in the mainhigh-voltage battery 83 may be discharged into the converter 106. Theconverter 106 may generate low-voltage power in the signal LVC. Theswitch 108 may route the signal LVC to the signal LVB to drive thehigh-power loads 94.

If the battery charger plug 110 receives power while in the state 146,the electronic control unit 114 may transition (e.g., PLUGGED) back tothe state 144. Thereafter, the electronic control unit 114 may commandthe switch 108 to route power from the signal LVD to the signal LVB todrive the high-power loads 94.

If the engine 72 is started while in the state 146, the electroniccontrol unit 114 may transition (e.g., ICE ON) back to the state 142.The electronic control unit 114 may command the converter 106 into thedown-conversion mode and command the switch 108 to route the low-voltagepower in the signal LVC to the signal LVB to drive the high-power loads94.

The state 148 may implement a wall charger mode. Upon a transition(e.g., CHARGE CMD) to the state 148, the electronic control unit 114 maycommand the switch 108 to connect the signal LVD to the signal LVC inthe state 148. The electronic control unit 114 may also command theconverter 106 into the up-conversion mode. In the up-conversion mode,the converter 106 may charge the main high-voltage battery 83 using thepower in the signal LVD as received through the battery charger plug110. In some embodiments, the switch 108 may also be commanded to routepower from the signal LVD to the signal LVB to recharge the auxiliarysystem backup battery 112. Once the main high-voltage battery 83, andoptionally the auxiliary system backup battery 112, are sufficientlyrecharged and/or the user chooses to end the recharging, the electroniccontrol unit 114 may return (e.g., NORMAL CMD) to the state 144 byissuing a set of commands to the switch 108 and the converter 106.

The state 150 may implement an auxiliary charge state. From the state146, the electronic control unit 114 may transition (e.g., CHARGE CMD)to the state 150. In the state 150, the electronic control unit 114 maycommand the switch 108 to connect the signal LVE to the signal LVC. Theelectronic control unit 114 may also command the converter 106 into theup-conversion mode. In the up-conversion mode, the converter 106 maycharge the main high-voltage battery 83 using the power in the signalLVE received through the auxiliary connector 124. In some embodiments,the switch 108 may also be commanded to route power from the signal LVEto the signal LVB to recharge the auxiliary system backup battery 112.Once the main high-voltage battery 83, and optionally the auxiliarysystem backup battery 112, are sufficiently recharged and/or the userchooses to end the recharging, the electronic control unit 114 mayreturn (e.g., NORMAL CMD) to the state 146 by issuing a set of commandsto the switch 108 and the converter 106.

If the battery charger plug 110 receives power while in the state 150,the electronic control unit 114 may transition (e.g., PLUGGED) back tothe state 148 and command the switch 108 to route power from the signalLVD to the signal LVC. If the battery charger plug 110 loses power whilein the state 148, the electronic control unit 114 may transition (e.g.,UNPLUGGED) to the state 150 and command the switch to route power fromthe signal LVE to the signal LVC. While five states are illustrated inthe example implementation, other numbers of state and transitiontriggers may be implemented to meet the design criteria of a particularapplication.

The functions performed by the diagrams of FIGS. 1-3 may be implementedusing one or more of a conventional general purpose processor, digitalcomputer, microprocessor, microcontroller, RISC (reduced instruction setcomputer) processor, CISC (complex instruction set computer) processor,SIMD (single instruction multiple data) processor, signal processor,central processing unit (CPU), arithmetic logic unit (ALU), videodigital signal processor (VDSP) and/or similar computational machines,programmed according to the teachings of the specification, as will beapparent to those skilled in the relevant art(s). Appropriate software,firmware, coding, routines, instructions, opcodes, microcode, and/orprogram modules may readily be prepared by skilled programmers based onthe teachings of the disclosure, as will also be apparent to thoseskilled in the relevant art(s). The software is generally executed froma medium or several media by one or more of the processors of themachine implementation.

The invention may also be implemented by the preparation of ASICs(application specific integrated circuits), Platform ASICs, FPGAs (fieldprogrammable gate arrays), PLDs (programmable logic devices), CPLDs(complex programmable logic devices), sea-of-gates, RFICs (radiofrequency integrated circuits), ASSPs (application specific standardproducts), one or more monolithic integrated circuits, one or more chipsor die arranged as flip-chip modules and/or multi-chip modules or byinterconnecting an appropriate network of conventional componentcircuits, as is described herein, modifications of which will be readilyapparent to those skilled in the art(s).

The invention thus may also include a computer product which may be astorage medium or media and/or a transmission medium or media includinginstructions which may be used to program a machine to perform one ormore processes or methods in accordance with the invention. Execution ofinstructions contained in the computer product by the machine, alongwith operations of surrounding circuitry, may transform input data intoone or more files on the storage medium and/or one or more outputsignals representative of a physical object or substance, such as anaudio and/or visual depiction. The storage medium may include, but isnot limited to, any type of disk including floppy disk, hard drive,magnetic disk, optical disk, CD-ROM, DVD and magneto-optical disks andcircuits such as ROMs (read-only memories), RAMS (random accessmemories), EPROMs (erasable programmable ROMs), EEPROMs (electricallyerasable programmable ROMs), UVPROMs (ultra-violet erasable programmableROMs), Flash memory, magnetic cards, optical cards, and/or any type ofmedia suitable for storing electronic instructions.

The terms “may” and “generally” when used herein in conjunction with“is(are)” and verbs are meant to communicate the intention that thedescription is exemplary and believed to be broad enough to encompassboth the specific examples presented in the disclosure as well asalternative examples that could be derived based on the disclosure. Theterms “may” and “generally” as used herein should not be construed tonecessarily imply the desirability or possibility of omitting acorresponding element.

While the invention has been particularly shown and described withreference to embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made withoutdeparting from the scope of the invention.

The invention claimed is:
 1. An apparatus comprising: a first interfaceconfigured to exchange a high-voltage signal with a high-voltage batteryof a vehicle; a second interface configured to receive a firstlow-voltage signal from a source external to said vehicle; a thirdinterface configured to present a second low-voltage signal to a powerrail of said vehicle, a converter configured to generate saidhigh-voltage signal by up-converting said first low-voltage signal whilein an up-conversion mode to recharge the high-voltage battery of saidvehicle, and (ii) generate said second low-voltage signal on said powerrail by down-converting said high-voltage signal received from saidhigh-voltage battery while in a down-conversion mode; and a switchconfigured to route a third low-voltage signal generated by saidconverter to said power rail in response to a command signal while saidapparatus is in a first mode.
 2. The apparatus according to claim 1,wherein said second low-voltage signal is generated in part from powerderived from an internal combustion engine of said vehicle, and saidvehicle is a hybrid vehicle.
 3. The apparatus according to claim 1,wherein said second low-voltage signal is generated solely from powerderived from said high-voltage battery of said vehicle and said vehicleis an electric vehicle.
 4. The apparatus according to claim 1, whereinsaid second interface is connected to said switch, and said commandsignal instructs said switch to route said first low-voltage signal tosaid power rail while said apparatus is in a second mode.
 5. Theapparatus according to claim 4, further comprising a fourth interfaceconnected to said switch and configured to receive a fourth low-voltagesignal, wherein said command signal instructs said switch to route saidfourth low-voltage signal to said power rail while said apparatus is ina third mode.
 6. The apparatus according to claim 5, wherein said switchis further configured to route said first low-voltage signal from saidsecond interface to said converter while said apparatus is in a fourthmode.
 7. The apparatus according to claim 6, wherein said switch isfurther configured to route said fourth low-voltage signal from saidfourth interface to said converter while said apparatus is in a fifthmode.
 8. The apparatus according to claim 4, further comprising alow-voltage battery connected to said power rail, wherein said switch isa break-before-make switch when changing between modes, and saidlow-voltage battery maintains power on said power rail while said switchbreaks all connections while changing between modes.
 9. The apparatusaccording to claim 1, further comprising an electronic control unitconfigured to control a mode of said apparatus in response to aplurality of commands received from a user interface device of saidvehicle, and control said converter between said up-conversion mode andsaid down-conversion mode.
 10. The apparatus according to claim 9,wherein said electronic control unit is further configured to report astatus of said switch to said user interface device.
 11. The apparatusaccording to claim 1, wherein said power rail has a first voltage in afirst range from approximately 10 volts to approximately 50 volts, saidhigh-voltage battery has a second voltage in a second range fromapproximately 200 volts to approximately 600 volts, and said power raildrives one or more loads up to 15,000 watts.
 12. A method for auxiliarypower distribution in a vehicle, comprising the steps of: exchanging ahigh-voltage signal between a high-voltage battery of said vehicle and afirst interface of a device; receiving a first low-voltage signal from asource external to said vehicle at a second interface of said device;presenting a second low-voltage signal to a power rail of said vehiclefrom a third interface of said device; generating said high-voltagesignal by up-converting said first low-voltage signal while in anup-conversion mode to recharge the high-voltage battery of said vehicle;generating said second low-voltage signal on said power rail bydown-converting said high-voltage signal received from said high-voltagebattery while in a down-conversion mode; and routing a third low-voltagesignal to said power rail using a switch in response to a command signalwhile in a first mode.
 13. The method according to claim 12, whereinsaid second low-voltage signal is generated in part from power derivedfrom an internal combustion engine of said vehicle, and said vehicle isa hybrid vehicle.
 14. The method according to claim 12, wherein saidsecond low-voltage signal is generated solely from power derived fromsaid high-voltage battery of said vehicle and said vehicle is anelectric vehicle.